1. Field of the Invention
The invention relates generally to a frequency stabilizing device of an oscillator and, more particularly, to a frequency stabilizing device in the application of an RC oscillator.
2. Description of the Related Art
An oscillator is an electrical circuit for generating a periodic signal, such as a sine wave or a square wave, which is divided into two groups: a harmonic oscillator and a relaxation oscillator. An RC oscillator is a harmonic oscillator, and only includes resistors and capacitors in the oscillation circuitry, without the use of inductors.
Typically, variations in the frequency of an RC oscillator are determined by the value of voltage. Please refer to FIG. 1. FIG. 1 illustrates variations in the frequency of oscillators related to different input voltages. A high voltage waveform 11 shows the waveform of the oscillator with a predetermined voltage. When the voltage of the oscillator decreases, the waveform becomes a low voltage waveform 12. Here, the frequency increases due to the amplitude of the low voltage waveform 12 being smaller than that of the high voltage waveform 11. Accordingly, the oscillator then generates more waveforms over a same period.
However, since the frequency of an oscillator is generally related to an input voltage, variations in the voltage of an oscillator causes variations in the frequency of the oscillator and results in circuit errors. Therefore, it is desirable to provide a frequency stabilizing device of an oscillator.